import java.util.logging.Logger;

class Circle{
    final float Pi =3.1415f;
    int r = 3;
    public float area(int r){
        return Pi*r*r;
    }
}

class TestJavaStructure {
    public static void main(String[] args){
        Circle c = new Circle();
        c.r =6;
    logger.sonarlint("圆面积:" + c.area(c.r));
    }
}